High performance donor materials

HGURE 5.2 (A) Structures of conducting polymers. (B) Representative high performance donor materials in polymer solar cell. (C) Representative fused aromatic ring building blocks for high performarxe donor materials. 

The innovations in materials science boost the development of polymer solar cell. Considering the four aspects mentioned previously, three methods have been developed accordingly (Li, 2012), namely side chain engineering, donor-acceptor (D-A) copolymerization and large fused aromatic ring structure. Some of the representative high performance conjugated polymers are displayed in Fig. 5.2B. 

As mentioned above, MDMO-PPV/PCBM is a model for studying reorganization features of PCBM and an amorphous donor material, both being not in their equilibrium state after device preparation. The obtained information can be applied to similar but modern and high-performance systems for the photoactive layer reaching actually 10% efficiency (status 2012). 

Very recently, several new classes of solution processible small molecule donors with favorable optical and electronic properties have been reported for use in OPV devices. When coupled with fullerene electron acceptors, such as [6,6]-phenyl-C7i-butyric acid methyl ester (PCy BM), solution processible small molecule based solar cells have achieved record PCEs over 8% for single layers devices and 10% for tandem cells. This chapter provides an overview of several important classes of solution processible small molecules used as donor materials in high performance OPV devices. For greater details on materials and devices, the reader is referred to several excellent reviews by Meerholz, Nguyen, Bauerle, Zhan, and Roncali. ... 

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